Wetland Terms – D

D [damsel fly–drainage basin]

damselfly: an aquatic macroinvertebrate of suborder Zygoptera. The larvae have three pairs of legs, one pair of antennae, and wing pads with feathery gills protruding from the abdomen. Larvae are somewhat sensitive to pollution.

daphnia: genus Daphnia; small freshwater crustaceans.

data: recorded observations and information.

data analysis: an evaluation of collected observations and information.

decomposers: a group of organisms, mainly fungi and bacteria, that digest organic material and release nutrients into the environment.

decomposition: the process of decay; the breaking down of organic matter into its component parts.

degrade: to reduce; to decompose by stages; to wear away by erosion.

degrees of latitude/longitude: angular units defined by circular lines around the Earth; used to measure distance north or south of the equator (latitude) and east or west of the prime meridian (longitude).

density: the mass of a substance per unit volume; the number of inhabitants per unit in a geographical region; the degree to which anything is filled or occupied; the degree of thickness.

dependent variable: a responding variable; a factor or condition that might change as a result of a change in a manipulated independent variable.

diatoms: phytoplankton of the class Bacillariophyceae. Diatoms are minute, unicellular or colonial algae having siliceous cell walls consisting of two overlapping, symmetrical parts.

dinoflagellates: a type of protist that includes photosynthetic forms in which two flagella project through armor-like plates. Abundant in oceans, these sometime reproduce rapidly, causing "red tides."

dissolved load: sediment made up of organic and inorganic material carried in solution by moving water.

dissolved oxygen (DO): the amount of oxygen dissolved in water; varies with water temperature and pressure; measured in milligrams of oxygen per liter of water, parts per million, or percent saturation.

distillation: a process used to clean water. Steam from a sample of boiling water is almost completely free of impurities. In distillation, the steam is collected and allowed to condense back into water.

diversity: variety; difference.

diving beetle: predatory aquatic beetles from the family Dytiscidae.

dNA: deoxyribonucleic acid; nucleic acid macromolecule that stores and transmits the genetic information of all living cells from one generation to the next.

dragonfly: an aquatic macroinvertebrate of the suborder Anisoptera. The larvae have three pairs of legs, one pair of antennae, and wing pads. Larvae are somewhat sensitive to pollution.

drainage basin: a watershed; the land area where precipitation runs into streams, rivers, lakes, and reservoirs. It can be identified by tracing a line along the highest elevations, often a ridge, between two areas on a map.